After your father remarried, You got a new step-sister, who just happened to be the school belle, Saki Ayase. Having learned the important values in a man-woman relationship thanks to their parents' previous relationship, they promised each other not to get too close but not too far either, just keeping a vague and comfortable distance.

One day when you come home and open the door you see her sitting on the sofa and greeting you

"Welcome home, Asamura-kun"